Automatic train-control system



1,628,634 y 1927' E. c. STAFFORD AUTOMATIC TRAIN CONTROL SYSTEM Filed Oct. 2, 1922 7 Sheets-Sheet 1 Zlnmmtoz Earl G Siaffofd 'LJLJLJLJLILJLJUIJUQLJLJLJLJLI E. c. STAFFORD AUTOMATIC TRAIN GONTROL SYSTEM ly ylilim Filed Oct. 2, 1922 7 Sheets-Sheet 2 gw-m tnioz Earl C. Stafford May 10,1927. 1,628,634

E. c. STAFFORD AUTOMATIC TRAIN CONTROL SYSTEM Filed Oct. 2, 1922 7 sheets-sheet 3 Earl C. Siafford 4 3 8 2 1 D R O F F A 5 c a May 10 1927.

AUTOMATIC TRAIN CONTROL SYSTEM 7 sheets-sheet 4 Filed Oct Earl G. Stafford 61 Henna May v 10 1927.

1,628,634 E. C. STAFFORD AUTOMATIC TRAIN CONTROL SYSTEM 1922 7 Sheets-Sheet 5 Filed 001.. 2.

5 wven tm,

Earl St afford May 10, 1927 G. STAFFORD AUTOMATIC TRAIN CONTROL SYSTEM Filed Oct. 2. 1922 7k Sheets-Sheet 6 Stafford Patented May 10, 1927.

UNITED STATES PATENT OFFICE.

EARL C. STAFFORD, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOB TO THE UNITED STATES TRAIN SIGNAL COMPANY, OF PORTLAND, MAINE, A CORPORATION OF MAINE.

AUTOMATIC TRAIN-CONTROL SYSTEM.

My said invention relates to an improved automatic block train control system embodying various improvements over the system disclosed in my prior Patent No. 1,327 ,17 6 January 6, 1920, and it is an object of the same to provide interlocking mechanical and electrical controlling devices by means of which a high degree of safety may be secured since they absolutely prevent a following train from entering a block already occupied.

A further object of the invention is to provide an electrically operated block train control in which the circuit is normally closed and in which breaking of thecircuit whether due to the presence of another train on the block or a defect in the signal system or any other cause will sci-veto stop the 1 train.

Another object of the invention is to pro-- vide such a system with interlocking safety devices that shall provide effectively against failure to operate.

Another object is to provide means whereby the engineer may increase the pressureon the brakes for an automatic stop without leaving his cab although he is precluded from releasing the brakes from this position after an automatic stop.

Other objects and advantages of the device will appear from the following specification.

Referring to the accompanying drawings, which are made a part hereof and on which similar reference characters indicate similar parts, 1

Figure 1 is a side view of a locomotive equipped with my devices,

Figure 2 a similar view of a tender to be attached to said locomotive,

Figure 3 an elevation of a ramp actuated shoe and parts cooperating therewith.

Figure 4 a right-hand elevation of parts shown in Figure 3,

Figure 5 a section on line 5--5 of Figure 3.

l igure 6 a detail of a portion of the ramp rail and supporting means therefor,

Figure 7 a view partly in section showing parts of the air brake system and a magnetic control valve therefor,

Figure 8 an elevation of a manually reset stick relay forming a part of the system,

with the casing in section.

Figure 0 a plan of the same with the cas mg in section,

Figure 10 a section on line 10-10 of Figure 11,

Figurcll a side view of the pump shown Figure 10,

Figure 12 a detail of the parts shown in Figure 10,

Figure 13 a diagrammatic view of the parts carried by the engine and tender with their connecting circuits, all shown in their normal position while the train is running,

Figure 14; a diagram indicating the relation of parts after the contact shoe or slipper has engaged a live ramp,

Figure 15 a diagrammatic view indicating the result of engagement with a dead r p,

Figure 16 a similar view indicating the position of parts when the hand reset for the system has been closed and the train is proceeding at low speed,

Figure 17 a diagrammatic view of a portion of a track in a double track railroad.

In the drawings reference character A indicates a conventional locomotive, B a conventional tender therefor, C a mechanism casing, D a manual resetting device, E a battery box, F an automatic brake valve, G an electrically-controlled valve, and H a speed governor, the parts so located on the engine and tender being the principal elements in my system which elements will hereinafter be described in detail. Figure 1 also shows a sealed three-way cutout cock K, a double-heading cutout cock L and a ramp M, the latter being mounted alongside the track and preferably on the ties.

Referring to Figure 6 a portion of the ramp M is here shown as being supported on two ties --30 by brackets 31 bolted to the ties. each bracket supporting a threaded member 32 which at its upper end is tired to the ramp rail. the tl'ireads at opposite ends permitting :uljuetuieut of me'l'nber 313 to correspond to the varying distances between the ramp and the ties at intervals a long the track. each ramp having a downwardly inclined portion at each end about 10 feet long and a ten foot horizontal section at the middle. The ramps are adapted for contact by shoes 33 which engage at the under side of the ramps, and the same operation takes place whether the train is running forward or back.

Figures 3, 4 and 5 show enlarged views of a shoe 33 and the parts adjacent thereto ltlll Shoes 33 are supported by a pivot 34 on brackets 35 fixed to a base plate 36 of mechanism casing C b bolts 37, the bolts being insulated from the bracket by insulation 38 and .the fbracket being separated from the base plate by insulation 39. The pivot shaft 34 has a collar 40 fixed to =itby pins-41 and is fixed to the bracket by pins 41. Torsion springs 42 are each secured at one end to the-collar and at the other end .to the-shoe. Brass bushings 34" separate the brackets 35 from pivotBt. Projecting rearwardly from the shoe is an arm 4t3 that bears on the underside ofa contact block tt on a. slidable tappet 44-1nounted in guides 45 on the base plate. The brackets 35 and' connected parts are covered by a housing 45 to protect them from injury.

The tappet extends up into a housing 46 "having a cover +17 at its front side with a suitable latch for keeping it closed. lVithin the housing is an electromagnet 48 connected by :a wire 49 to the shoe 33 andby another wire 50 to a round 51 (Figure 13). An armature 52 is supported by a weighted bracket pivoted at .53, this bracket having at its upper end a .detent 5% cooperating with a .hook 55 fixed to the ,tappet. The bracket also carries a laterally extending hook 56 adapted to he engaged by a pin '07 on the slidable tappet. In case a shoe should be lost the corresponding ,tappet would fall and the pin 57 would engage hook 5 6, the weight of the .ta et serving to pull the armature away from the magnet and so break the circuit through the-valve G and stop the train as hereinafter set 'forth. Pin'57 also prevents closing. of the circuit at 58, '59 unless the itappet is properly raised, due to its ongagement with the hook 56. At the opposite side of the detent 54 is ,an insulated Contact member 58 adapted to be engaged by a pair of contacts 59 mounted .on and insulated from vasupport 6O fixed to the base. The tappet also carries a v movable circui.t cont-rolling element comprising a support 61 and a series of blocks 61. A spring 62 bears at one end against a guide 45 and at the other against a shoulderon the tappet and tends to ,force the tappet downward. These blocks are arranged to cooperate with spring con-- tacts 63 on a circuit closing block 64 fixed to the base 36.

Air brake control naive.

. fromthe operators brake valve to the automatic brake valve which is connected by pipes .67 and 68 and a connecting passage prises an electro-magnet 72 'ture 73 formed at its upper end as a valve operators valve directly to the three way cock and it will be seen that by reason of the presence of this bypass the operators valve inay operate independently of the automatic brake valve by turning the handle from the full line position where it is held by a seal 71 to the dotted line position. Such operation is, however, recorded due to thebreaking of the seal. In ordinary practice the operators valve can ahto he operated for emergency application of the matic bralze valve. as will ttPPGtll' litltlllttller. The electrically controlled valve (x coinbrakes without interfering with the autowith an armato close a down going l'n'anch of an air passage 74, this branch leading to exhaust openings 75. So long as the electro-magnet is energized the passage will he closed by said valve. When the magnet is deenergized the inlet end of the passage will be closed. by a valve 76 fixed to or supported by the armature. The air in these passages comes through the pipe 77 connected to the main reservoir and in the position of parts shown in the drawings goes through the passageway 74: to a pipe 78 leading to a chamber 78 in the automatic brake valve underneath the piston 79 and holds the piston against a leather washer 80. The piston 79 hasa two- 'partstem 81 on which are a pair of valves 32 and 83 the valve 83 being adapted to close the iassage through the brake valve from the train pipe to the exhaust which in this instance consists of an aperture in a plug 9!. the aperture being reduced at its outer end to form a small leak port. lVheu the air pressure under the piston fails the piston moves downward the upper valve 32 seats itself and so closes the passage through the automatic brake valve to prevent pasnagje at air from the main reservoir. It does not in tert'ere with the operation of the brakes by means of the operator's valve a"; valve 8:? i?" merely a check valve inojvably connec ed, to valve 83 by joint 82. The electro-nagnet 72- is energized hya circuit conniiris ng a conductor leading to ground 86 and another conductor 87 leading to the uppermost spring contact 63 on the block 64:. A eonductor 88 is also adapted to contact under certain circumstances with said segment. this conductorbeing connected to a battery and then to ground.

I may also mount on the valve body a set retaining valve body 39 h ving a pnsragw opening into the automatic brake valve this passage being normally closed by a valve 90 under adjustable spring pressure. lVheu the air pressure is admitted to the automatic brake valve by the lowering oi piston Til the ill] lit!

Hand reset stick relay.

The tender shown in Figure 2 carries a manually reset circuit breaker for a wiring system on the train, details of which are shown in Figures 8 and 9 and the location of which with reference to the remaining mechanism is illustrated in Figures 13 to .16. Referring to Figures 8 and 9 the device comprises an outer casing encloa-ing the entire device and supporting an inner casmg 103 containing the core 01 an electroma net connected to the battery in box E by conductors 104. and 105 (Furs. 8, 13 and 1.6). The electromagnet has an armature consisting of a disk 10? to which a brass rod 106 is connected by a screw-thread to permit adjustment of the rod relatively to the disk. At its upper end the rod carries a fiber pin to engage a circuit closer. When the electromagnet is tie-energized the disk and rod fall so far that the head 108 of the rod rrsts on a fiber pin 109 in the upper end of a rod 109 located in a bore at the lower end of the casing, said rod having a collar to support it on the floor of the casin The headed rod serves to lift the armature into the field of operation of the electromagnet, the lowermost position of the disk being such that it can not be elevated merely by energization of the electromagnet. The magnet casing has a lower extension 110 secured by screws to the outer casing and is held in place at its upper end by a U-shaped bracket 111. the bracket having its arms bent laterally at their upper end and having also 'a bore through which the brass rod passes. Insulating washers 112 are applied to said arms and a post 113 extends through each of them thus providing a connector on the one arm for a contact 114 adapted to engage a pair of contacts 115 mounted on the other arm. A conductor 1.16 leads to the contact 114 and the contacts 115 are connected respectively to conductors. 117 and 1.18 by the posts 113. The armature being lifted and the magnet energizedthe rod 106 will be maintained in the position shown, and so will hold the contact 114 against the two contacts 115.

Safety speed controlling device. The safety speed controlling device is of the pum on the piston 1529 and thus varv shown in detail. in Figures 10 to 12 and also appei'irs in l igrurcs l 13 to 16. This device may be operated by a special motor but is here shown as actuated from the cres. brad 119 by a connection. comprising a link 11:31) and a rock arm 121 secured to a rocl.,1att The rockshait't 122 has a pair of cranks connected respectively by links 12; and 1241 to pump pistons 125 and 1213. These pistons operate in parallel bores in a cylinder 12? con'nnunirniting with a cylinder 128. The cylinder 128 contains a piston 129 having near its upper end a transvcrse slot to receive the enlarged head of a rockarm 131) on a shaft 131. This shaft also carries a cam 132 adapted to actuate a lever 133 by engagement with a similar cam 1231 thereon. The lever 133 is c0nnected to a flexible contact member 1341 adapted to engage a second contact 135 to close a circuit diagramn'iatically shown in the remaining figures. Should the pump :tail to work the piston 129 will remain in its lowest poT-ii 1011 and the cam 131 will fail to ride under and lift up the cam on lever 133. A. float 136 rests on the oil in the lower chamber of the casing H and this float carrics a rod engaging a recess in the under side of the rockarni 130. The float holds the arm 139 up in substantially the posit-ion shown, but it the oil falls too low the arm falls and breaks the circuit. A leak passage .137 on the piston permits the oil to bypass from under the piston when the level. in the casing low. In the alisence of such a passage it will be seen that the piston might be held up until. the casing was practically dry. The oil from the leak passage 137 passes through leak ports 137 in the cylinder 198 at a, distance from the bottom of the cydindcr corresponding to the distance be tween the bottom of the piston and the upper end of leak passage 137. By this arrangement the piston can gradually sink to the bottom of the cylinder. The ports 137' are so located as to serve also to prevent excessive pressure by permitting the oil to escape after the piston has been raised to a sullicicnt height. A pipr 138 is connected to the cylinder adjac uit its lower end and extends upward into casing provided with a pin valve 139. A pipe 140 leads back into the chaml' er from the other side of the pin valve. This valve provides means For adjusting the escape passage to vary the oti'ect the predetcnnincd lnaxin'uu'n speed when the s1 111al-controlled lHllTOmtlhC stop devices are out of action.

In the operation of my device he position of parts on the train during normal operation between ramps will be as shown in Figure 13 and at this time current will pass from the engine battery through conductr88, block 61, conductor 87, magnet G, and conductor 85 to ground at 86. Unle the train is moving between ramps the parts will remain in the position of Figure 1, op-

eration of the brakes being prevented by the valve on armature 73 which is held in .place as in Figure 7 to prevent escape of air from the bra-king system.

hen the shoe 38 contacts with alive ramp-it is moved as in Figure 1 1, raising the'tappet is above the detent 54:. The magnet 1-8 becomes energized as explained below, and attracts the armature 52 carrying detent 54: and "contact 58. This position of the armature will permit the tappet to return to normal position after the ramp is passed and also "closes the circuit through contacts 58 and "59, 59. When the tappet is in raised position the'current from the engine battery 141 passes through conductor 88, block 142,

conductors 143 and 118, contacts 59, 58, 59,

conductor 144, magnet and conductor 85 to ground. The group of contacts 63 should preferably be so spaced that one of the two circuits for energizing magnet Gwvi ll be closed just before the other is opened thus preventing loss of pressure in the brake system.

- It may be stated here that in the case of ,a live ramp current passes through a roadside battery 115, a pivoted circuit closer 14.6, a stationary contact 147, a conductor .148, the ramp M, shoe 38, conductor 49, magnet 18 and so to ground at 51. The track is divided into a plurality of blocks as indicated at N, O, P in Figure 17 and each block has connected across the rails a track battery 149, the battery energizing a'circuit comprising a conduclor 150 leading to one rail of the track, a conductor 151 leading from this rail to an electromagnet 152, a conductor 153 leading from the magnetto the other rail of the trackand a confductor 154 extending from that rail .to the battery. The electromagnet 152 is normally energized by this circuit to hold the circuitcloser 146 in closed position. 'Assuming'the system here shown to be used with home distant s aals of the type shown in Patent 1 ,176 the tr in to be ,.ovingin the direction of the arrow it will be se it that the home signal at the right hand side of Figure 17 evidently set at danger, the train being in the block 0 and eh rt circuiting the battery of that block whereby the corresponding magnet 152 is deenergized and ,the switch is open thereby producing a dead ramp. At the same time the distant signal in the block N will have been moved to caution position.

Figure shows the position of parts resulting when a train encounters a dead ramp such as is shown at the left of Figure 17. The shoe 33will of course raise the tappet 4.4: and inasmuch as magnet 18 is dccnergizcd by reason of the opening of the circuit at 1 16, 1 1-7, the detent 51 will be free and by reason of the weight at one side of its pivot it will be swung over against the lappet thereby engaging under the shoulder 55 and preventing the tappet from returhing to its lowermost position. The circuit leading from the engine battery through conductors 88 and 87 will be broken as in Figure 1 1 and the circuil leading from the engine battery through conductors 88, 143, 118 and 11-1 will remain open due to the movement of the detent whereby the contact 58 is ren'ioved from contacts 59, 50. The electromagnet G being thus dcencn gized the armature 78 will fall, thus opening the valve. The air will escape and the brakes will be set.

After being thus stopped the engineer can nevertheles proceed at a low speed which may be predetermined according to the circumslances ot the particular railroad or suhdbxisiou thereol. For this purpose the manual rc-setting device or stick iclay D is provided. It is located under the tender so that the engineman must get out 01 his :ab to operate it. It will be seen that when this stick relay is moved to closed position a; in Figure 113 by operation of the plunger rod 109 (Figure 8) a circuit will he closed from the engine battery 111 through conductor 88, block 142, conductor 1123, contacts 115, 111, conductor 110, block 155, conductor 156, circuit closer 1S1 (Figures 10 and 1(3), stationary contact 185, conductor 10 1 magnet 103, conductor 105, and so to ground at 157. The magnet lUSserves to hold the hand reset stick relay in closed position against the action 01 gravity, but does not raise it when ithas once iallcn. A branch circuit is also closed by actuation of rod 101) through. the engine ballcry 111, the conductors 88, 14-2, 118, the contacts 115, 116, 115, conductor 117, brake magnet G, and conductor 851:0 ground at 86. At this time the tappet is locked in upper position but on encounter with a dead ramp will stop the train by breaking the connection between block 155 and wire 156, thus deenergizing magnet 108. To insure running only at a speed lower than a predetermined speed, the governor illustrated in Figures 10 to is introduced into the system. So long the desired low speed is maintained. the pumps 125 and 120 will raise the piston 129 only so high as to maintain the cam 1352 under the cam on the lever 138 and thus hold the switch elclnenls in closed relation to each other. Should a higher speed be attained at any time the pumps will be operated so rapidly as to raise the piston to a greater height and thereupon the cam on the rock arm will move the cam on lever 133, thus permitting the lever to fall and open the circuit. hen this takes place the a magnet 103 becomes deenergized and the armature of the stick relay falls, interrupting the brake circuit and causing the air brakes to be applied. Should the pumps fail to lift the piston 129 the cam 132 will pass the cam 133 in the other direction and allow the lever to fall thus opening the switch and causing the circuit via conductor 116 to be opened because of the failure of magnet 103.

Should the train pass a live ramp while in the condition of Figure 16 the ramp will raise the tappet and, being electrified, it will also cause the magnet 48 to be energized. The magnet will attract its armature, thus retracting the detent 54 to permit the tappet-to falh and will also close the circuit at 58, 59, 59 until the ramp is passed. The parts are now in position to resume high speed travel which may be continued until interrupted by a signal or some defect such as a broken rail, a break in the circuit or the like, which can produce an eifect like that of a stop signal. The circuit through wires 116, 156, block 155, etc., will be closed only when the train is proceeding at loW speed under the conditions of Figure 16, and will be broken Whenever a rampis encountered by the shoe. This circuit when so broken will not be restored, as the train is now traveling at increasing speed, and the control by the automatic stopping devices is now resumed.

By moving the lever (Fig. 7) I may cut out the entire automatic control and leave the train under control of the engineer alone. When this is done the seal 71 broken to indicate the occurrence to a train inspector or other ofiicial.

The system designed so as to be readily applicable to existing apparatus. It forms a reliable interlocking connection between the air brakes and the signal apparatus whereby trains may be fully controlled in a predetermined manner.

Many variations in the system and parts thereof may be made without departing from the spirit of my invention the true scope of which is indicated in the appended claims.

\Vhile I have shown the pump in Figures 10 and 1.1 as driven by an osci lating shaft it may be connected to a rotating member of the locomotive by a silent chain or the like. i

Having thus fully described mysaid invention, what I claim as new and desire to secure by Letters Patent, is:

1. A block control system for railway trains comprising train stopping means, a normally closed electric circuit restraining operation thereof, an auxiliary circuit adapted to restrain operation of the train stopping means, a circuit closer common to both c rcuits, a ramp for each block, a block-sigother circuit at one point, a detent to hold the circuit closer in the actuated position, and an electrormrgnct in circuit with said ramp to inhibit the action of the detent when a clear track is indicated, substantially as set forth.

2. A block control system for railway trains comprising train stopping means, a normally closed electric circuit restraining operation thereof, an auxiliary circuit adapted to restrain operation of the train stopping means, a circuit closerconnnon to both circuits, a ramp for each block, a' blocksignal-controlled circuit for each ramp, a shoe on the train adapted to be actuated by a ramp for operating the circuit closer to open the main circuit at one point and close the other circuit at one point, a detent to hold the circuit closer in the latter position, and an electromagnet in circuit with said ramp to inhibit the action of the detent when a clear track is indicated, a part of the auxiliary circuit being mounted on said detent whereby said circuit also is interrupted when the ramp circuit is broken, substantially as set forth.

3. A block control system for railway trains comprising train stopping means, means normally restraining operation thereof including a normally closed main electric circuit, an auxiliary circuit also adapted to restrain operation of the train stopping means, a ramp for each block, a block-signalcontrolled circuit for each ramp, means for alternately interrupting and restoring the two circuits in passing a live ramp, means for interrupting both circuitsvin passing a dead ramp, at third controlling circuit for the restraining means, and a circuit closer common to the three circuits, substantially as set forth.

4. A. block control system for railway trains comprising train stopping means, means normally restraining operation thereof including a main electric circuit, an auxiliary circuit adapted to rest 'ain operation of the train stopping means, a: ramp for each block, a block-signal-controlled circuit for each ramp, means for alternately interrupting and restoring the two train circuits in passing a live ramp, means for interrupting both circuits in passing a dead ramp, :1 stick relay inaccessible while the train is moving for closing a third controlling circuit for the restraining means, and meansv to limit the speed of travel while said third circuit is closed, substantially as set forth.

5. A block control system for railway tra'ins comprising train stopping means, means normally restraining operation thereof including a main electric circuit, an auxiliary circuit adapted-to restrain operation of the force of gravity, a circuit for said electromagnet. including said ramp, and means operated by a train in the block for breaking the latter circuit, substantially as set forth.

14. In a block control system for railway trains, a circuit closer comprising a fixed member and a movable member, a lever engaging the movable member, a cam on the lever, a cam mounted for oscillation beneath the first and adapted to open the circuit at either extreme of its movement and close it in central position, a pump operated by a moving part of the engine, and a piston actuated b the pump to operate the circuit closer, su )stantially as set forth.

15. In a block control system for railways, a train brake ipe, an operators brake valve, a pipe leadlng from said valve to the train pipe, a valve casing in said pipe having an open leak port, a valve to prevent access of air to the leak port, a piston for actuating the last-named valve, a passage leading from a source of fluid pressure to a chamber under said piston, an electrically controlled normally open valve in said passage, whereby pressure is maintained on the piston to hold in closed position the valve actuated thereby, an emergency bypass pipe leading around said valve and joined at both ends to the operators brake pipe, a three way cock atthe junction farthest from the operator, and a seal for said cock, substantially as set forth.

16. A block control system forrailway trains comprising train-stopping means, means for restraining operation thereof including an electric circuit, a vertically movable circuit closer therefor, a ramp for each block, a block-signal-controlled circuit for each ramp, a shoe on the train adapted to be actuated by the ramps for lifting said circuit closer to break the main circuit, an auxiliary circuit closed by said circuit closer When lifted, and means for breaking both circuits on loss of said shoe, substantially as set forth.

17. A block control system for railway trains comprising trainstopping means, means for restraining operation thereof including'an electric circuit, a vertically movable circuit closer therefor, a ramp for each block, a block-signal-controlled circuit for each ramp, a shoe on the train adapted j to be actuated by the ramps for lifting said circuit closer to break the main circuit, an auxiliary circuit closed by said circuit closer when lifted, a switch in the auxiliary circuit, and means on the circuit closer for opening said switch on loss of said shoe, said circuit closer also simultaneously breaking the main circuit, substantially as set forth.

18. A block control system for railway trains comprising train-stopping means,

means for restraining operation thereof including a main electric circuit, a circuit closer adapted to open said circuit at either extreme of its movement and close the same in intermediate position, ramps along the track, a roadside battery for each ramp, an electron'iagnet on the train, a circuit partly on the train and partly on the ground connecting the battery and the electromagnet, an armature for the elcctroiuagnct, an auxiliary circuit on the train, a circuit closer therefor moving with said armature, a shoe for actuating the firstaiamed circuit closer to break and restore the main and auxiliary circuits in alternation and means whereby the first-named circuit closer breaks the main circuit on loss of a shoe and also moves said armature to break the auxiliary circuit, substantially as set forth.

19. A block control system for railway trains comprising train-stopping means, means for restraining operation thereof including a main electric circuit, an auxiliary restraining circuit, a circuit closer adapted to open one of said circuits at one extreme of its movement and the other at the other extreme, and a second auxiliary restraining circuit having a gap closed by said circuit closer in the first named extreme position, substantially as set forth.

20. A block control system for railway trains comprising train-stopping means, means for restraining operation thereof including a main electric circuit, a circuit closer adapted to open said circuit at either extreme of its movement and close the same in intermediate position, ramps along the track, a roadside battery for each ran'ip, an electromagneton the train, a circuit partly on the train and partly on the ground connecting the battery and the electromagnct, an armature for the electrcmagnet, an auxiliai'y circuit on the train, a, circuit closer therefor moving with said armature, a shoe for actuating the first-named circuit closer to break and restore the main and auxiliary circuits in alternation, andmeans whereby the three circuits are broken on loss of a shoe, sui'istantially as set forth..

21. In a train control system, autoi'natic control devices including a main circi'iit, an auxiliary circuit adapted to be manually closed when the main circuit is broken, an electromagnet having an arn'iature adapted to maintain the auxiliary circuit in closed relation, a circuit closer in the circuit of the electromagnct, and a pump on the train adapted to break theflcircuit on excessive speed thereof, substantially as set forth.

22. In a train control system, automatic control devices including a main circuit, an auxiliary circuit adapted to be manually closed when the main circuit is broken, an electromagnet having an armature adapted to maintain the auxiliary circuit in closed relation, a circuit closeninthe circuit, of the electromagnet, a, pumponthe train adapted to break the last-named circuit on excessive speed thereof, a casing for, the pump, a body ofiliquid in the casing, and means for breaking said'last named circuit whentheliquid falls below a predetermined level, substan: tially as, set V forth.

23;,Ina traiircontrol system, automatic cQntrol;devicesincluding, a main circuit, an auxiliary circuit adapted to be manually nosed when, the main circuit is, brok electromagnet; having an armature adaptcd tomaintain, the auxiliary circuit in closed relation, a circuit closer in the circuit of the electromagnet a, pump onthe train, a hy- "draulic ram, operated thereby, and connections. from the. piston. of; the ra n. to saidv circuit closer whereby; excessive upward ,movement of the; piston of the rain breaks saidicircuit, substantially as sct forth.

2 4; In a train control system, automatic controldevices includinga. main circuit, an

auxiliary circuit; adapted to be manually ,closedwhcnthc ma n circuit broken, air electromagnet hav ng, an armature adapted to maintain the auxiliary-c'ircuit in closed relation, acircuit closer in the circuit of the clectromagnet, apumpon the train, ahyidraulic ram operated; thereby, connections from the piston of the ram. to said circuit closer whereby excessive upwardmovement of; the, piston breakssaid circuit, and leak ports limiting the, upward movement of; said a piston, substantially asset fortln 25. In a, train control, system, automatic control devices including a main circuit, an auxiliary circuit adapted to be manually closed-When the main circuit is broken, an electromagnethaving an armature adapted to maintain the auxiliary circuit; in closed relation, acircuitcloser in the circuit of theelectromagnet, a pump on the train, ahydraulic, ram operated thereby, connections from the pistonof the ranrto said circuit closer wherebyexcessive upward movementof the piston breaks Said circuit, a bypass for the liquid coming fronrthe pump and,

means for adjusting the size otthe bypass to Vary the etfectof the pump on the piston, suhstanti ally as, set forth,

26. In a train control system,automatic control-devices including a main circuit, an.

auxiliary circuit adapted to be manually closedwhen' the main circuit is broken, an,

electromagnet having an armature adapted to maintain the auxiliary circuit in closed relation, a circuit-closer in the circuitof the electromagnet, a pung p on the train, a hydraulic ram operated thereby, connections from the pistonof theflram to said circuit closer whereby excessive upward movement. of-the, PlSilOl'l bIGZtkSSitld circuit, leak ports limiting the upward movement of the piston, anrla leak'passagc in the PaSl'OH coop crating with said leak ports to enable the piston to sink to the bottom of the cylinder, substantially as, set forth 27. In a train control system, automatic control devices including a main circuit, an auxiliary circuit adapted to be manually closed when; the main circuit is broken, an electrgm agnet having. an armature adapted to maintain the auxiliary circuit in closrcd relation, a circuit closer in the circuit of the electromagnet, a pump on the train, a h draulic ram operated thereby, (ftlllllttilOllS fronrthc piston of the ranrto said circuit closer whereby excessive upward nmrci'neut of thepiston breaks said circuit and an equalizing passage permitting the liquid in the cylinder of the raur to find the same level, as that. in the casing for. the. pinup, substantially as set forth.

28, In a train control system, autoiuatic controldeviccs including; :rmain circuit, an auxiliary circuit ad u ted to be mauinilly closed when the main circuit broken, an elcctro nagmd having airarmalure. adapted toimaintain the auxiliary circuit in closed relation. and means for breaking the circuit ofthe electromagnet oncxcessivc speed of the train,substantially as. set forth.

29.- A block control systcnr for railway trainscomprising trainstopping means, a normally closed electric circuit restraining operation thereof, an auxiliary circuit, a ramp for each block, a lJl0cl(-signul-.controlled circuit for each ramp, means for alternately interrupting and restoring the two traincircuits inpassing an lire ramp, means for interrupting-both circuits in passing a dead ramp, athird controlling circuit for said restraining means, manual means for closing said circuit, a-fourth circuit multaneously closed by saidimanual mcans, a circuitcloser in the third circuit, an electromagnet in the fourth circuit adapted to hold saidcircuit closer in closed position, and specddimiting means for breaking said fourth circuit whenthe, train exceeds a predetermined limit, substantially as set: forth.

30. A block control, system fora railway trains. comprising train stopping means, a normally closed electric circuit restraining operation thereof, an auxiliary circuit, a ramp for each block, a, block-signal-controlledcircuit for each amp, means for alternately interrupting and restoring the two train circuits in passing alive ramp, means for interruptingv both circuits in passing a dead ramp, a third controlling circuit for said restraining; means, gravity actuated manualmcans for closing said circuit, a fourth circuit,simultaneously closed by said manual means, a gravity-actuat-ed circuit closer in the third circuit. an clcctromagnet in the fourth circuit adapted to hold said circuit closer in closed position, and speedliiniting means for breaking said fourth iltl circuit when the train exceeds a predetermined limit, substantially as set forth.

31. In a train control system, train stopping means and means for restraining the same from operation compr' mg a main electric circuit, roadside devices to interrupt the main circuit, an auxiliary circuit supplementing the action of the main circuit when the track is clear, a permissive low-speed circuit, and a circuit closer connnon to said eircuits movable by gravity into position to close the main circuit, said, circuit closer being lifted positively by said roadside devices, substantially as set forth.

32. A train control system comprising an air brake controlling valve, a normally energized electromagnet for maintaining the valve in closed position, a gravity-controlled circuit closer for making and breaking the circuit through said electromagnet, a gravity controlled detent adapted to hold said circuit closer in one position, and. an electromagnet adapted to hold said detent out of operative engagement with said circuit closer, substantially as set forth.

$13. A train control system comprising an air brake controlling valve, a normally energized clectron'nignet for maintaining the valve in closed position, a circuit closer biased to close the circuit of the electromagnet, a detent for holding the circuit closer in open position, an electroi'i'mgnet adapted to restrain the (fletent from engagement with the circuit closer, rimdside devices for ac touting said circuit closer to break the circuit, and a second circuit for energizing the first-named elcctromagnet said. second circuit including a part of said detent, substantially as set forth.

In witness whereof, I have hereunto set my hand at Washington, District of Columbia, this 27th day of September, A. D. nineteen hundred and twenty-two.

EARL O. STAFFORD. 

